Heat motor for a rotary ice tray



J. K. LUND ETAL 3,020,727

HEAT MOTOR FOR A ROTARY ICE TRAY Feb. 13, 1962 Filed Nov. 2, 1959 3Sheets-Sheet 1 Z 2 619,94 6 fiw/zzzs/A/ b W a Ty J. K. LUND ETAL3,020,727

HEAT MOTOR FOR A ROTARY ICE TRAY 5 Sheets-Sheet 2 Feb. 13, 1962 FiledNov. 2, 1959 F 50 go J 22 I t 7' 18 ii 3* IJUVEJYTQPE Feb. 13, 1962 J.K. LUND ETAL 3,020,727

HEAT MOTOR FOR A ROTARY ICE TRAY Filed Nov. 2, 1959 3 Sheets-Sheet 3.Ewg. 9

JEYPEHTUPE 4/4MEJ 14 10MB dezeey C. delvauner ('42; C. fl/waezn/v UnitedStates Patent 3,020,727 HEAT MOTOR FOR A ROTARY ICE TRAY James K. Lund,Northfield, Carl C. Bauerlein, Lincolnwood, and Jerry C. Janquart,McI-Ienry, Ill., assignors to The Dole Valve Company, Morton Grove,111., a corporation of Illinois Filed Nov. 2, 1959, Ser. No. 850,371 8Claims. (Cl. 62138) This invention relates to an ice making apparatusand more particularly relates to an automatic ice making apparatus ofthe type adapted to be mounted within the usual freezing compartment ofa household refrigerator or the like.

Automatic ice makers of the type adapted to be used in householdrefrigerators have recently found wide acceptance although theirmarketability has been somewhat restricted due to the fact that the icemakers which have thus far been devised have been relatively expensiveto produce and have had several undesirable features which it is theobject of this invention to eliminate.

This invention is more specifically directed to an apparatus operable topivotally move an ice tray through an ice-block ejection cycle as afunction of the temperature of the fluid within the molds in the icetray.

This invention may find utility in operating a pivotal ice tray which iselongated in configuration and which has a plurality of molds spacedalong the longitudinal axis thereof and facing in opposite directionsand disposed in heat transfer relation with one another, though theinvention should not be construed as being so limited. The type of icetray mentioned above is adapted to function in the following manner:

Each of a plurality of upwardly facing molds are filled with waterthrough a slug valve or through a time-fill valve and are then allowedto cool until they have frozen into ice blocks. Subsequent to freezingof the water within each of the molds into ice blocks the elongated trayis rotated so that the ice molds filled with the frozen ice blocks aredisposed in a downwardly facing direction and so that another pluralityof upwardly facing molds are disposed in a position to receive water.Relatively warm water is then dispensed into the upwardly facing moldsand the heat of the water filling the upwardly facing molds istransferred through the heat conducting walls of the ice tray to meltthe surfaces of the ice blocks in the downwardly facing molds to breakthe bond between those ice blocks and their respective molds thuspermitting the ice blocks to fall by the force of gravity into acollection tray. Subsequent to freezing of the water disposed in theupwardly facing molds the tray is again rotated to dispose those moldsin a downwardly facing direction and to dispose the molds which havejust been freed of their ice blocks in a position to receive water. Thecycle is thus repeated.

1 contemplate mounting the pivotal ice tray on a shaft journalled withina slide wall of a freezing compartment and effecting rotatable movementof the ice tray in the following manner.

Two thermal sensitive elements having power members extensible therefromupon predetermined ambient temperature conditions therearound aredisposed in coaxial alignment with one another with their power elementsin opposed relation. A gear rack interconnects the outer free ends ofeach of the power elements and is, in turn, cooperab-le with a spur gearfixed to the shaft journalled within the wall of the freezingcompartment upon which the pivotal ice tray is mounted. Resistor heatersare wound about each of the thermal elements to provide a means forheating the elements to effect extensible movement of their respectivepower members. By energizing one of the resistor heaters, the powerelement associated with the thermal sensitive element upon which theresistor heater is wound will move extensibly to effect longitudinalmovement of the gear rack. Such movement of the va result, each of thethermal sensitive elements are mounted slidably in their respectivesupports and are generally maintained in a fixed position by means ofovertravel springs which are compressible to permit slidable movement ofthe thermal elements within their respective supports after the movementof the gear rack has been interrupted by the gear rack stops.

A cam lever interconnects each of the thermal elements and is soarranged that it will pivotally move with respect to one of the thermalelements upon overtravel of either of the thermal elements. By placing aswitch having a depressible plunger adjacent the cam lever in such amanner that the plunger is depressed upon pivotal movement of the camlever, the switch will be actuated whenever either of the thermalsensitive elements slidably moves within its respective support. Asolenoid for controlling operation of a fluid line valve may beenergized through this switch so that filling of the ice tray iseffected during that time interval when the plunger is depressed by thepivoted cam lever.

It is therefore a principle object of the present inven-- tion toprovide a new and improved mechanism for ef-' Yet another object of theinvention is to provide a low cost and readily assemblable mechanism foreffecting pivotal movement of an ice tray.

These and other objects of the invention will appear from time to timeas the following specification proceeds and with reference to theaccompanying drawings, wherein:

FIG. 1 is a front elevational view of an ice making apparatusconstructed in accordance with the principles of the present inventionshown mounted in the wall of a freezing compartment;

FIGURE 2 is a fragmental front elevational view of the adjacent ends oftwo thermal sensitive elements with a cam lever interconnecting thoseends and showing the relation of the cam lever with an electricalswitch;

FIGURE 3 is a fragmental view which is similar in nature to FIGURE 2 butwhich shows the cam lever in a different position;

FIGURE 4 is a schematic wiring diagram of the embodiment of theinvention illustrated in the drawings;

FIGURE 5 is an enlarged front elevational view of the mechanism foreffecting pivotal movement of the ice tray; I

FIGURE 6 is a fragmental view illustrating the gear rack and itsassociation with the opposed power members of a pair of thermalsensitive elements;

FIGURE 7 is a horizontal sectional view through the side wall of thefreezing compartment showing the cooperation between the gear rack andthe spur gear and the associated electrical switches;

FIGURE 8 is a fragmental view of the gear rack and the associated spurgear from a different position, showing some parts in vertical sectionand others in side elevation and also illustrating the selector switchand its associated components;

FIGURE 9 is afragmental front elevational view showing a portion of thethermal sensitive element support in vertical section and showing thethermal sensitive element in an overtravel position;

FIGURE 110 is a side elevational view of the mechanism for effectingpivotal movement of the ice trai and FIGURE 11 is a fragmental viewwhich is similar in nature to FIGURE 10 but which shows one of thethermal sensitive elements in an overtravel position.

Referring initially to FIGURE 1, a pivotal ice tray 10 is mounted on ashaft 11 for corotatable movement therewith while the shaft is, in turn,journalled for rotatable movement within the wall 12 of a freezingcompartment 13. A filler spout 14 is also mounted within the wall 12 andterminates adjacent and above the pivotal ice tray 10 to provide a meansfor filling the ice tray with water to be frozen into ice blocks.

The ice tray 10 has a plurality of ice molds 15 formed therein along thelongitudinal axis thereof which are defined by oppositely and angularlydisposed side walls 16 and 17. End walls 18 are disposed at each end ofthe tray and serve, like the partition walls 19, to define the sidewalls of each of the respective ice molds. Another plurality of seriallyaligned molds is formed on the opposite side of the ice tray. Each ofthese molds has one wall defined by the wall 16 so that the wall 16 iscommon to the oppositely facing molds. The entire ice tray isconstructed of aluminum or some other material which is a good heatconductor so that when relatively warm water is directed to the upwardlyfacing molds, when the ice tray is in the position illustrated in FIG-URE l, the heat of water filling those molds will be transferred throughthe heat conducting walls of the ice tray to melt the surfaces of theice blocks in the downwardly facing molds to permit gravitationalejection of the ice blocks within the downwardly facing molds 15 into asuitable collection tray.

Referring now more particularly to FIGURE 5, a boss 20 which extendsfrom the end wall 18 of the ice tray 16 is threadedly mounted on theshaft 11 which is journalled for rotatable movement within the wall 12of the freezing compartment 13. A pin 21 extends through the boss andinto the'shaft 11 to key the tray to the shaft for corotatable movementtherewith. The outer end of the shaft 11 has a spur gear 22 affixedthereto, through which pivotal movement is transmitted to the ice tray10. A gear rack 23 is disposed adjacent the spur gear 22 with its teethin mesh with the peripheral teeth of that gear so that longitudinalmovement of the gear rack will act to effect rotatable movement of thespur gear and consequent pivotal movement of the ice tray.

A three-legged support 25 is secured to the outer surface of thefreezing compartment wall 12 and has spaced outwardly extending legs 26and 27 formed integrally therewith which have coaxially alignedapertures 28 and 29, respectively, formed therein. Bearings 30 and 31are fitted within the apertures 28 and 29, respectively, and are adaptedto slidably receive the cylindrical casings 32 of a pair of opposed andaxially aligned thermal sensitive elements 33 and 34.

Each of the thermal sensitive elements 33 and 34 is of a type which iswell known in the art, including a heat sensing portion 36 forcontaining a fusible thermally expansible material, a guide portion 37,and a power member 38 which is slidably disposed within the guideportion 37 and which is extensible from the thermal sensitive elementupon fusion and expansion of the material within the heat sensingportion 36 thereof.

In order to facilitate an explanation of this device the power memberwhich is guided within the thermal sensitive element 34 is indicated asmember 38 while the power member associated with the thermal sensitiveelement 33 is indicated as member 39.

A radially enlarged collar 40 is formed about each of the thermalsensitive elements which acts as a stop, limiting movement of thethermal sensitive elements in a manner which will hereinafter becomemore fully ap parent.

Each of the thermal sensitive elements has a collar 41 fitted on theoutermost end of the guide portion 37 thereof against which are disposedarms 43 and 44 for reasons which will hereinafter become apparent. Thearms are biased into engagement with the collars 41 by means ofovertravel springs 45 and 46 (associated with the elements 33 and 34,respectively) and these springs abut at their opposite end portions, theoutturned flanges of the bearings 30 and 31. The overtravel springs 45and 46 thus serve not only to urge the arms 43 and 44 into engagementwith the collars 41 but also serve to bias the thermal sensitiveelements 33 and 34 so that the radially enlarged portions 49 thereof aredisposed in engagement with the outer surfaces of the outwardlyextending legs 26 and 27.

The outer end portions of the power members 38 and 39 are connected tothe gear rack 23 or, if so desired, may be formed integrally therewithso that the power members and the gear rack move with one another.

Heater coils 48 and 49 are wound about the heat sensing portions 36 ofthe thermal sensitive elements 33 and 34, respectively, and provide ameans for heating the elements to effect extensible movement of theirrespective power members.

Thus, assuming that the various parts are disposed in the positionillustrated in FIGURE 5, energization of the heater coil 48 will act toheat the material within the thermal sensing portion 36 thereof toeffect extensible movement of the power member 39, Extensible movementof the power member 39 will move the gear rack 23 (as shown in FIGURES 5and 6) downwardly to thereby rotate the spur gear 22 in acounterclockwise direction (as shown in FIGURE 8) while simultaneouslyacting to retractably move the power member 38 within the thermalsensing unit 34. Thereafter, by deenergizing the heater coil 48 andenergizing the heater coil 49 the power members and the gear rack willbe returned to the position illustrated in FIGURE 5 and the spur gear 22and the ice tray, which is corotatable therewith, will move in aclockwise direction (as shown in FIGURE 8) to its initial position.

Referring now more particularly to FIGURE 4, the heater coils 48 and 49are energizable through a selector switch 50 and a line switch 51 from apower source indicated at 52.

The selector switch 50 and its associated components are more clearlyshown in FIGURE 8. The selector switch 50 is mounted on an outturned leg54 which is formed integrally with the support 25 and which extendsoutwardly therefrom intermediate the legs 26 and 27. The switch 50 has adepressible plunger 55 which extends entirely therethrough and which isshown as pro truding from the lower surface thereof. Upon depressionalmovement of the plunger 55 from the position illustrated in FIGURE 8,the plunger will then be moved to a point in which it extends exteriorlyof the upper surface of the switch. When the plunger 55 is in theposition illustrated in FIGURE 8 the movable contact of the switch willbe disposed in the position illustrated in FIGURE 4 so that closure ofthe line switch 51 will effect energization of the heater coil 48.

The arms 43 and 44 are so bent that the arm 44 which is connected to theguide portion of the thermal sensitive element 34 is disposed adjacentthe upper surface of the switch 50 while the arm 43 connected with theguide p0rtion of the element 33 extends and is disposed adjacent thelower surface of the switch 50. The arm 43 is ported as at 57 to permitthe extension of the arm 44 therethrough.

It will be observed, in view of the foregoing, that when the element 33begins to move against the opposing biasing force of the overtravelspring 45, the arm 43 will contact the depressible plunger 55 and shiftthe movable contact within the switch 50 from the position illustratedin FIGURE 8 to a position operable to effect energization of the heatercoil 49. Thus, the selector switch will be actuated whenever one of thethermal sensitive elements moves in overtravel.

As shown most clearly in FIGURES 6 and 7, the gear rack 23 has anelongated boss 60 protruding from the base thereof which is slidablyreceived within a complementary channel in the leg 54. The gear rackalso has a pair of cars 61 extending from the opposite sides thereofwhich are received within channel grooves 62. Thus, when the powerelement 38 moves extensibly from the thermal sensitive element 34 thegear rack will be slidably moved within the complementary grooves in theleg 54 until the ears 61 abut the terminal walls defining the ends ofthe channel grooves 62. Thereafter, since the power member 38 cannotfurther move extensibly from the thermal sensitive element 34, theelement '34 will move in overtravel against the opposing biasing forceof the spring 46 to effect actuation of the selector switch 50 in themanner which has hereinbefore been described and to effect consequentdeenergization of the heater coil 49 and substantially simultaneousenergization of the heater coil 48.

As shown diagrammatically in FIGURE 1, a solenoid actuated shut-offvalve 70 is disposed in a fluid line for controlling fluid flow throughthe filler spout 14 to the ice tray 10. Opening of the shut-off valve iseffected by means of energization of a solenoid coil associatedtherewith. The solenoid coil is illustrated diagrammatically in FIGURE 4and is indicated at 71.

Energization of the solenoid coil 71 is controlled through a movablecontact within a switch 73, which contact, as diagrammaticallyillustrated in FIGURE 4, is normally biased by a spring to an opencircuit position. As shown in FIGURE 7 the line switch 51 is secured tothe leg 54 and the switch 73 is, in turn, mounted on the switch 51.

FIGURES 2 and 3 illustrate the means devised to effect actuation of theswitch 73 and only fragmentarily illustrate the coacting parts in orderto clarify the drawings.

- A cam lever 75 has one end thereof secured to the arm 43 while theopposite end thereof, which comprises an inclined cam surface 76 (bentat an angle with respect to the remainder of the lever) is slidablydisposed within an elongated slot 77 formed in the arm 44. The switch 73is disposed (as indicated in FIGURES 2, 3 and 7) adjacent the lever 75so that pivotal movement of the lever will effect axial movement of theplunger 78 which, in turn, is operably connected with the movablecontact of the switch to open and close the energizing circuit to thesolenoid coil 71. Thus, whenever the thermal sensitive elements, andconsequently the arms 43 and 44, move relatively away from one anotheras from the position illustrated in FIGURE 2 to the position illustratedin FIGURE 3, the lever 75 will be pivoted in a clockwise direction aboutits point of connection with the arm 43 by engagement of the portion ofthe arm 44 defining the slot 77 with the cam surface 76 to elfectdepressional movement of the plunger 78 and consequent closure of themovable contact within the switch 73 thereby energizing the solenoidcoil 71 and eifecting filling of the upwardly facing molds within theice tray 10. Such relative movements of the thermal sensitive elementsaway from one another will, of course, be effected whenever one of thethermal sensitive elements moves in overtravel. Finally, energization ofthe entire ice making apparatus is effected through the line switch 51which, in turn, is actuated as a function of the temperature of fluidwithin the upwardly facing molds in the ice tray 10. Referring onceagain to FIGURE 5, an elongated cylinder 80 is disposed within the icetray 10 along the pivotal axis thereof and is adapted to contain a fluidwhich is expansible upon cooling. The interior of the cylinder 80 is inopen communication with a central bore 81 in the boss 20 and that boreis, in turn, closed by a flexible annular diaphragm 83. The diaphragm 83is secured within the hollow interior of the boss 20 by engagement withthe outer end of the shaft 11. It will be noted that the shaft 11 isalso relieved as at 84 to permit flexure of the diaphragm 83.

A motion translation rod 85 abuts the diaphragm 83 and is disposedwithin an axial bore formed in the shaft 11 and the spur gear 22 andterminates at a point adjacent the plunger 87 of the electrical switch51. The plunger 87 is, of course, operably linked with the movablecontact of the switch (which is shown in FIGURE 4) so that depressionalmovement of the plunger 87 will act to close the electrical circuittherethrough. It will be noted at this juncture that the switch 73 andthe cam lever 75 have been deleted from the illustration of theapparatus in FIGURE 5 in order to clarify that drawing.

Assuming that the various parts of the ice tray rotating mechanism areinitially in the positions illustrated in FIGURES l, 2, 4, 5, 6 and 8and that the upwardlyfacing molds within the ice tray are filled withwater to be frozen into ice blocks the operation of the mechanism may bedescribed as follows:

Upon cooling of the fluid within the cylinder 80 the fluid will expandto force the diaphragm 83 outwardly and to consequently slidably movethe rod 85 within the axial bore in the shaft 11 to depressionally movethe plunger 87 in switch 51 and effect closure of the movablecontacttherein to thereby energize the resistor heater 48.

When the resistor heater 48 is energized the fusible thermallyexpansible material within the element 33 will be heated andconsequently expand to extensibly move the power member 39 therefrom.Extensible movement of power member 39 will act to retractably move thepower member 38 within its respective thermal sensitive element and tolongitudinally and downwardly move the gear rack 23. Such downwardmovement of the gear rack 23 will act to rotatably move the spur gear 22in a counterclockwise direction (as viewed in FIGURE 8) to rotate theice molds illustrated in FIGURE 1 to an upwardly facing directionpreparatory to filling thereof. When the stops 61 abut the end walls ofthe channel grooves 62 further longitudinal movement of the gear rack 23will be prevented so that the thermal sensitive element 33 will beforced to slidably move within the bearing 30 against the opposingbiasing force of the overtravel spring 45.

I When the thermal sensitive element 33 thus moves in overtravel, therelative distance between the opposed ends of the two thermal sensitiveelements will be lengthened so that the cam lever will be pivoted fromthe position illustrated in FIGURE 2 to the position illustrated inFIGURE 3 and the plunger 78 in switch 73 will thereby be depressed toenergize the solenoid coil 71 and effect filling of the ice tray 10. I

Also, during this interval when the thermal sensitive element 33 ismoving in overtravel the arm 43 will engage the end of the plunger 55extending exteriorly of the lower surface of the switch 50 to move themovable contact within that switch from the position illustrated inFIGURE 4 to a position to effect subsequent energization of the heatercoil 49. The heater coil 49 will thus be energized almost simultaneouslywith deenergization of the heater coil 48.

Upon energization of heater coil 49 the power member 38 will begin tomove extensibly to effect retractable movement of the power member 39and consequent return upward movement of the gear rack 23. Such returnupward movement of the gear rack 23 will, of course, act to rotatablymove the spur gear 22 and consequently the ice tray in a clockwisedirection (as viewed in F1"- URE 8).

It will be understood that upon deenergization of the heater coil 48 thefusible thermally expansible material within the element 33 will bepermitted to cool so that the element will be returned to its normalposition illustrated in FIGURE by overtravel spring 45. Such returnmovement of the element 33 will of course act to decrease the distancebetween the mating opposed ends of the thermal sensitive elements sothat the cam lever 75 will return from the position illustrated inFIGURE 3 to the position illustrated in FIGURE 4 to effect consequentdeenergization of the solenoid 71 and to thereby shut-off fluid flow tothe ice tray 10.

Subsequently the heat of water filling the upwardly facing molds withinthe ice tray will be transmitted to the fluid within the cylinder 80through the heat conducting walls of the ice tray and the diaphragm 83,rod 85, and the plunger 87 will be returned to the position illustratedin FIGURE 5 so that the movable contact within switch 51 will bedisposed in the open circuit position thereby preventing further cyclingof the apparatus until the water within the upwardly facing molds in theice tray has frozen into ice blocks.

Each of FIGURES 9 and 11 clearly illustrates the position of thermalelement 34 and its associated components when that element is moving inovertravel in order to clarify the operation of the device.

It will be understood that this embodiment of the invention has beenused for illustrative purposes only and that various modifications andvariations of the present invention may be effected without departingfrom the spirit and scope of the novel concepts thereof.

We claim as our invention:

1. In an ice making apparatus comprising a support, an ice trayjournalled within said support and disposed within a freezingcompartment, means for filling said ice tray with fluid to be frozeninto ice blocks, said ice tray being rotatable to permit gravitationalejection of ice blocks therefrom, the improvement of means for rotatingsaid ice tray comprising a shaft connected to said ice tray along therotational axis thereof, a mechanical transducer tangentially disposedrelative to said shaft and drivingly connected therewith, power meansdisposed at opposite ends of said transducer, and means for alternatelyenergizing said power means to effect longitudinal movement of saidtransducer and consequent rotational movement of said shaft and tray,said power means being movably mounted relative to each other in thedirection of movement of said transducer.

2. In an ice making apparatus comprising a support, an ice trayjournalled within said support and disposed within a freezingcompartment, means for filling said ice tray with fluid to be frozeninto ice blocks, said ice tray being rotatable to permit gravitationalejection of ice blocks therefrom, the improvement of means for rotatingsaid ice tray comprising a shaft connected to said ice tray along therotational axis thereof, a mechanical transducer tangentially disposedrelative to said shaft and drivingly connected therewith, power meansincluding thermally expansible material disposed at opposite ends ofsaid transducer, and means for alternately energizing said power meansas a function of the temperature of fluid within said freezingcompartment to effect longitudinal movement of said transducer andconsequent rotational movement of said shaft and tray.

3. In an ice making apparatus comprising a support, an ice trayjournalled within said support and disposed within a freezingcompartment, means for filling said ice tray with fluid to be frozeninto ice blocks, said ice tray being rotatable to permit gravitationalejection of ice blocks therefrom, the improvement of means for rotatingsaid ice tray comprising a geared shaft connected to said ice tray alongthe rotational axis thereof, a gear rack tangentially disposed relativeto said geared shaft and drivingly connected therewith, power meansdisposed at opposite ends of said gear rack and means for alternatelyenergizing said power means as a function of the temperature of thefluid within said freezing compartment to effect longitudinal movementof said gear rack and consequent rotational movement of said shaft andtray, said power means being movably mounted relative to each other inthe direction of movement of said gear rack, and said means for fillingsaid ice tray with fluid being responsive to the distance between saidpower means.

4. In an ice making apparatus comprising a support, an ice trayjournalled within said support and disposed within a freezingcompartment, means for filling said ice tray with fluid to be frozeninto ice blocks, said ice tray being rotatable to permit gravitationalejection of ice blocks therefrom, the improvement of means for rotatingsaid ice tray comprising a shaft connected to said ice tray along therotational axis thereof, a pair of thermal sensi tive elements mountedwithin said support having power members extensible therefrom uponpredetermined ambient temperature conditions therearound coaxiallyaligned and having their power members disposed adjacent one another, amechanical transducer tangentially disposed relative to said shaft anddrivingly connected therewith and connected at its opposite ends withsaid power member, heater means associated with each of said elementsfor effecting extensible movement of the respective power memberstherefrom, and means for alternately energizing said heater means toeffect longitudinal movement of said transducer and consequentrotational movement of said shaft and tray.

5. In an ice making apparatus comprising a support, an ice trayjournalled within said support and disposed within a freezingcompartment, means for filling said ice tray with fluid to be frozeninto ice blocks, said ice tray being rotatable to permit gravitationalejection of ice blocks therefrom, the improvement of means for rotatingsaid ice tray comprising a geared shaft connected to said ice tray alongthe rotational axis thereof, a pair of thermal sensitive elementsmounted within said support having power members extensible therefromupon predetermined ambient temperature conditions therearound coaxiallyaligned and having their power members disposed adjacent one another, agear rack drivingly connected with said geared shaft and connected atits opposite ends with said power members, heater means associated witheach of said elements for effecting extensible movement of therespective power members therefrom, and means for alternately energizingsaid heater means to effect longitudinal movement of said gear rack andconsequent rotational movement of said sraft and tray.

6. In an ice making apparatus comprising a support, an ice trayjournalled within said support and disposed within a freezingcompartment, means for filling said ice tray with fluid to be frozeninto ice blocks, said ice tray being rotatable to permit gravitationalejection of ice blocks therefrom, the improvement of means for rotatingsaid ice tray comprising a geared shaft connected to said ice tray alongthe rotational axis thereof, a pair of coaxially aligned thermalsensitive elements slidably mounted within said support having powermembers extensible therefrom upon predetermined ambient temperatureconditions therearound and having their power members disposed adjacentone another, a gear rack interconnecting the free ends of said powermembers and drivingly engaging said geared shaft so that longitudinalmovement of said rack will effect rotatable movement of said gearedshaft and consequently said ice tray, heater means associated with eachof said elements for effecting extensible movement of the respectivepower members therefrom,

abutment means formed on each of said elements, means biasing saidelements toward one another to maintain said abutment means on each ofsaid elements in engagement with said support, means limiting the amountof longitudinal movement of said gear rack, and switch means foralternatingly energizing said heater means operable as a function ofchanges in relative distance between said thermal sensitive elements.

7. In an ice making apparatus comprising a support, an ice trayjournalled within said support and disposed within a freezingcompartment, means for filling said ice tray with fluid to be frozeninto ice blocks, said ice tray being rotatable to permit gravitationalejection of ice blocks therefrom, the improvement of means for rotatingsaid ice tray comprising a geared shaft connected to said ice tray alongthe rotational axis thereof, a pair of coaxially aligned thermalsensitive elements slidably mounted within said support having powermembers extensible therefrom upon predetermined ambient temperatureconditions therearound and having their power members disposed adjacentone another, a gear rack interconnecting the free ends of said powermembers and drivingly engaging said geared shaft so that longitudinalmovement of said rack will effect rotatable movement of said shaft andconsequently said ice tray, heater means associated with each of saidelements for effecting extensible movement of the respective powermembers therefrom, abutment means formed on each of said elements, meansbiasing said elements toward one another to maintain said abutment meanson each of said elements in engagement with said support, means limitingthe length of travel of said gear rack, switch means for alternatelyenergizing said heater means operable as a function of changes inrelative distance between said thermal sensitive elements, and switchmeans operably controlling said tray filling means and actuatable duringthose intervals whenever one of said thermal sensitive elements hasslidably moved within said support to move its abutment means out ofengagement therewith.

8. In an ice making apparatus comprising a support,

an ice tray journalled within said support and disposed within afreezing compartment, means for filling said ice tray with fluid to befrozen into ice blocks, said ice tray being rotatable to permitgravitational ejection of ice blocks therefrom, the improvement of meansfor rotating said ice tray comprising a geared shaft connected to saidice tray along the rotational axis thereof, a pair of coaxially alignedthermal sensitive elements slidably mounted within said support havingpower members extensible therefrom upon predetermined ambienttemperature conditions therearound and having their power membersdisposed adjacent one another, a gear rack interconnecting the free endsof said power members and drivingly engaging said geared shaft, heatermeans associated with each of said elements for efiecting extensiblemovement of the respective power members therefrom, abutment meansformed on each of said elements, means biasing said elements toward oneanother to maintain said abutment means on each of said elements inengagement with said support, means limiting the amount of longitudinalmovement of said gear rack, means for alternately energizing said heatermeans, and switch means for controlling operation of said tray fillmeans actuatable during those intervals when at least one of saidthermal sensitive elements has slidably moved within its support to moveits respective abutment means out of engagement with said support.

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